360 



REAGENTS AND THEIR PREPARATION 



[Ch. X 



soluble glycogen one can use 50% alcohol 300 cc. instead of water. 

 The iodin stain is the most precise and differential for glycogen. 

 Tissues or embryos for glycogen are fixed and hardened in 95% or 

 absolute alcohol, and sectioned by the paraffin or by the collodion 

 method. For permanent preparations the paraffin method is best 



Fig. 211-213. Bottles for Fixing and Preserving Tissues. 



Fig. 2ii.- Wide mouth specimen bottle with glass stopper. 

 Fig. 212. Salt mouth bottle with glass stopper. 

 Fig. 213. Glass jar with screw top. 



(§ 623). In spreading the sections use this iodin stain instead 

 of water. Glycogen in the sections stains a mahogany red, and the 

 stain remains for ten or more years in the spread paraffin sections. 

 Spread sections may be stained or restained by immersing the slide 

 in iodin stain. 



Before mounting permanently, deparaffin with xylene, and mount 

 in melted yellow vaseline. Press the cover down gently. Seal with 

 shellac or balsam. (Gage, Trans Amer. Micr. Soc, 1906, pp. 203-205.) 



